Electric cable.



G. BARTELS. ELECTRIC CABLE. APPLICATION FILED AUG. 26, 1908.

966,644. Patented Aug. 9, 1910.

1 QZ LZQM 0%? UNETED GEQRG BARTELS, OE NIPIES, HEAR GQLOGNE, GERIVKANY, ASSIG-NOR TO COMPANY LAND UNI) SE ABFLW' W W V' IENG QQ AFT, OF NIPPES, "NEAR COLOGNE,

GERMANY, A GQRPORATIGN CABLE.

9661344. Specification of Letters Iratent.

Application filed August 28, Serial l lo,

' as even to destroy the cable to its very core,

contact will he made between two auxiliary conductors at an earlier moment than that at which the insulation of the conductor carrying the main current is injured with the re sult that a cut-outswitch or equivalent device is set in operation, so that no sparking can talre place at the point of injury to the cable.

In carrying out this invention the main conductors (of which there may be one or more) carrying the main or strong current are inclosed in strong highly elastic electrically insulating material, and are surrounded by two outer concentric auxiliary conductors for carrying the Weak current. These two auxiliary conductors are separated from each other by a thin layer of pliable insulating material much less resistant to mechanical strain than the insulating material inclosing the main conductor or conductors. The Whole is then surrounded by a coveringof highly elastic electrically insulating material, with or Without an outer casing of lead or other protecting covering.

The accompanying drawing illustrates by Way of example one form of cable construct ed according to this invention in cross section with a diagram illustration of the arrangementof the main features of the external circuits of the ereral conductors.-

Z indicates the conductors carrying the strong current. There may be one or more of these conductors. Three are shown in the drawing. These conductors Z are surrounded by a strong and highly elastic electrically insulating material 6. Around the whole of the conductors Z and material 6 there are arranged in the usual manner two concentric braided metal casings or windings m, m

which are separated from each other by a thin layer oi phab material 8 that is capaole ct being broken or damaged with compo atiye ease relatively to the material by which the main current conductors are insulated.

A layer it of highly elastic electrically insulating material is laid around the outermost of the auxiliary concentric conductors m 1229. Around this layer it, there may be arranged as usual either an impregnated braiding or an armored lead casing.

The two outer auxiliary conductors are arranged in series in a circuit- "includiug a lOW tension current battery 7), and an electromagnet 7. This electromagnct when excited attracts the latch L, tripping the switches or cut outs S, S, S S, etc, all of which are mounted on one shaft it partly broken away portions of which are diagrammatically represented ingthe Cll tiVJ- in g, or otherwise connected so a n unison. The effect of the operation of he sw'tches is to open the circuits between the generator G, and the cables Z at l3, l3, E and to ground all the cables Z and concentric conductors. m m by closing the ground connection at X, X, X, fi fid X Thus the current from the generator is shut off and all parts of the cable are grounded so that no arc can form at the point of rupture or elsewhere in its length. flow it the cable working say, in a mine, be subjected to an excessive mechanical strain, then before the electrically insulating covering of the conductors carrying the strong current, can yield the comparatively readily destroyed layer between the concentric auxiliary conductors will allow of a short-circuit being produced between these latter, which will operate the automatic cut-out device situated on the surface.

i I claim and desire to secure by Let ters i s-tent of the llnited States, is?

l. in elcct'ic cable comprising one or more main conductors for strong current inclosed in highly elastic electrically insulating material, surrounded by two outer concentric auxiliury conductors for week current that are separated from each other by a thin layer of pliable insulating material much less resistant to mechanical strain than the insulating material inclosing the main conductors, the whole being surrounded by a co ei ng of highly elastic electrically in- *1 sulating the pin-nose hereinbefore described.

2. The combination with an electric cable having an inner conducting portion and insulating covering of relatively high tensile strength, anti an outer covering comprising two conducting sections and intervening insulation of low tensile strength, of a source of heavy current connected to the inner conductors, and means operated by a current flowing through the two outer conducting sections when the same are short circuited to cut out the source of heavy current supply.

3. The combination with an electric cable having an inner conducting portion and insulating covering of relatively high tensile material, substantially as and for strength, and an outer covering comprising two conducting sections and intervening inducting portions of the cable.

In testimony whereof I have hereunto set my hand 1n presence of two subscrlbmg Witnesses.

GEORG BARTELS.

Witnesses CHARLES LE SIMPLE, M. Kiirrnns. 

